Study On Overall Stability Bearing Capacity Of Welded High Strength Steel Box Section Beam Column

In recent years, High strength steel(fy=460MPa)welded box section members have been successfully applied in many steel structure engineering, and achieved good economic benefits. Code for design of steel structures(GB50017-2003)for the welded box section members width thickness ratio of the high strength steel is too strict, the bearing capacity can not be fully utilized. Relax the limiting width-thickness ratio appropriately, can not only give full play to the performance of high strength steel, but also reduce the cost of saving steel. At present, the overall stability bearing capacity of high strength steel members for research mostly focused on the axial compression member, for the common beam column in practical engineering research is relatively small. in this paper, the Q460 steel welded box section bending members overall stability of the bearing capacity are studied.The establishment of Q460 steel welding width to thickness ratio of the finite element model of box section beam column by the finite element software ANSYS, to study the width-thickness ratio, slenderness ratio, load eccentricity and cross section length ratio on the bearing capacity of its stability, and with considerable compares the stability bearing capacity of Q235 steel structure members, finally combining with the specification for design of steel structures(GB50017-2003)and North American specification for the design of cold-formed steel structural members(AISI2004), proposes and revised is suitable for high strength steel welded box section beam column Q460 stable bearing capacity design formula.Research shows that the finite element model is built in this paper can well simulate width-thickness ratio transfinite overall stability of welded box section beamcolumn. Width-thickness ratio increases, the ultimate bearing capacity of the members,by overall buckling instability failure gradually turned to local buckling; Slenderness ratio increases, the overall stiffness decreases, the ultimate bearing capacity reduced,prone to overall instability; The increase of the section length of limit bearing capacity increases, prone to overall buckling;Increasing load eccentricity and ultimate bearing capacity of the components is reduced, prone to overall instability.Compared with the equivalent of Q235 steel members, the ultimate bearing capacity of the Q460 steel components has improved significantly, and the influence of residual stress on the stable bearing capacity of the Q235 steel members. Revised the design formula of direct strength method has good accuracy, the calculation results tally well with the finite element calculation results, and be safe.